new: tests go in separate file, minor cleanup in snippet.el
fix: respect 80 column rule mostly
fix: set local variables correctly, i.e. dont set lexical-binding here
fix: slightly terser loop syntax
fix: correctly allow functions as snippet forms

also make define-snippet expand directly to a defun
fix: don't require lexical-binding to call transforms with field text
fix: provide a simple edebug spec for define-snippet
new: make-snippet makes an anonymous snippet lambda

bug: apparently broke edebug though
add: ert-based test-suite